This invention is directed to ribbon cartridges and, more particularly, to ribbon cartridges suitable for use in printers, particularly line printers.
VARIOUS TYPES OF RIBBON CARTRIDGES SUITABLE FOR USE IN PRINTERS AND THE LIKE HAVE BEEN PROPOSED BY THE PRIOR ART. The ribbon cartridges generally fall into two groups, endless and non-endless. The non-endless cartridges generally include a takeup reel and a supply reel and the ribbon moves from the supply reel to the takeup reel, as required, during printer operation. In some instances the ribbon is reusable and the supply and takeup reels switch functions when all or substantially all of the ribbon has moved from the supply reel to the takeup reel. In some cases the printer operator is required to invert the ribbon cartridge to extend its life.
The other types of ribbon cartridges, which are of more significance to the present invention, are endless cartridges. In endless cartridges an endless ribbon is moved from one aperture in a cartridge housing, through the printer mechanism, and back to the cartridge housing. In some cartridges the ribbon is merely "stuffed" into the cartridge housing. In other cartridges, the ribbon is drawn into a ribbon roll. As ribbon is removed from one end of the roll and fed into the printer, ribbon is continuously added to the other end of the roll, with individual roll loops sliding with respect to one another.
Endless ribbon cartridges proposed by the prior art vary from relatively complicated to relatively unsophisticated cartridges. Examples of relatively complicated printer ribbon cartridges, at least with respect to their internal structure, using a "stuffed" technique are described in U.S. Pat. Nos. 3,814,231 and 3,830,351, both issued to Samuel D. Cappotto, the first for a "stuffed Ribbon Cartridge" and the second for a "Typewriter Ribbon Cartridge For Endless Loop Ribbon." Examples of somewhat similar cartridges using a ribbon roll technique are described in U.S. Pat. Nos. 3,643,777 issued to Carl P. Anderson et al. for "Typewriter Ribbon Cartridge" and 3,643,779 issued to Carl P. Anderson, et al. for "Ribbon Mechanism for Cartridge Supported Ribbons." In addition to their somewhat complicated internal mechanisms, the cartridges described in these patents have the further disadvantage that they are designed such that ribbon enters and leaves the cartridge housing from generally the same slot whereby the housing must be greater than twice the width of the tape in height or thickness.
A somewhat less complicated endless ribbon cartridge structure is described in U.S. Pat. No. 3,524,602 issued to Pierre J. Green et al. for "Endless Ribbon Cartridge." While this patent describes an arrangement somewhat similar in its broad aspects to the present invention, as will be better understood from the following description, it lacks certain features thereof. For example, it does not provide for a capstan drive mechanism to "pull" ribbon into a cartridge housing. Further, it does not provide for inking of the ribbon internally in the housing. Moreover, while it includes a tensioning spring, the spring does not act to align the ribbon with an exit aperture whereby ease of accurate withdrawal of the ribbon, without ribbon breakage, is not provided.
As will also be better understood from the following description, one of the features of the invention is that the ribbon is in the form of a Mobius strip. While this general ribbon form has been proposed before by the prior art (see U.S. Pat. No. 3,460,666 issued to W. Ploeger, Jr. for "Endless Printing Ribbon"), the prior art has not proposed the use of a Mobius strip ribbon in an endless loop cartridge wherein a majority of the ribbon length forms a roll housed in a cartridge housing. Without this feature only a limited amount of ribbon is available for use.
Therefore, it is an object of this invention to provide a new and improved endless, printer ribbon cartridge.
It is a further object of this invention to provide a capstan driven endless printer ribbon cartridge.
It is another object of this invention to provide an endless loop capstan driven printer ribbon cartridge.
It is yet another object of this invention to provide a Mobius strip, endless loop, capstan driven, printer ribbon cartridge wherein a majority of the printer ribbon forms a roll housed within a cartridge housing, even when the capstan driven printer ribbon cartridge is mounted for use in a suitable printer.